In this application note, we describe a method to determine total protein using AAA-Direct. We used this method to participate in an Association of Biomolecular Resource Facilities (ABRF) Amino Acid Analysis Research Group collaborative study that compared total protein determinations using AAA to dye-binding assays. We found that concentrations of all five protein solutions determined by AAA-Direct were equivalent to the determinations made by participants that used either pre- or postcolumn derivatization methods.

This application note describes the use of HPAE- PAD to determine sucralose in food and beverage samples. Red Raspberry Diet Rite is a soft drink artificially sweetened with sucralose. It also contains natural and artificial flavors, organic compounds (potassium benzoate and citrate), food dye, and another nonnutritive sweetener (acesulfame potassium). These model food and beverage samples present a great challenge for most chromatographic methods. In this note, the CarboPac™ PA20 anion-exchange column is used to separate sucralose from other ingredients in Red Raspberry Diet Rite and Splenda.

This application note describes the use of AAA-Direct to analyze common amino acids in the presence of simple sugars, sugar alcohols, alcohols, and glycols in yeast and bacterial fermentation broths. In this application note, the AminoPac PA10 anion-exchange column is used to separate amino acid and carbohydrate ingredients in cell culture and fermentation broth media. High carbohydrate concentrations can hamper the determination of some amino acids due to coelution. Also in this application note, disposable gold (Au) electrodes are evaluated for use in amino acid determination.

Specific amperometric waveform integration ranges can provide a tool to selectively detect specific compounds. 3-D amperometry enables postchromatographic modification of waveform integration ranges, simplifying the procedure by eliminating the need for multiple injections. This technique can enhance the detection of carbohydrates in the presence of some coeluting amino acids. Additionally, it can minimize some baseline disturbances improving peak integration. Peak area response can conveniently be adjusted to match values from older HPAE-IPAD chromatography systems.

In this Application Note, the use of AAA-Direct for Trp determinations is investigated in proteins, peptides, and cell cultures. AAA-Direct technology provides both complete separations of all common amino acids using AminoPac PA10 and the direct detection of amino acids by integrated pulsed amperometric detection (IPAD).We present a new isocratic method designed to rapidly elute Trp while separating it from free amino acids, carbohydrates, and peptide fragments. This method reduces the run time to as short as 12 min, significantly increasing throughput compared to conventional techniques.